1. Field of the Invention
The present invention relates to a semiconductor manufacturing apparatus, a liquid container and a semiconductor device manufacturing method.
2. Related Art
A semiconductor device such as a NAND flash memory is required to bury a silicon oxide film in a trench having a high aspect ratio so as to form deep STI (shallow trench isolation) in a narrow region.
To meet this demand, a film formation technique for using both an HDP (high density plasma) film and an SOG (spin on glass) film has been developed (see Japanese Patent No. 3178412). According to this technique, a silicon oxide film is deposited by HDP-CVD (chemical vapor deposition), and a film coated with a perhydropolysilazane liquid (hereinafter, “PSZ (Polysilazane)”) is coated on the silicon oxide film by spin coating. The coated film is then silicified by a cure treatment. It is thereby possible to bury the silicon oxide film in a trench having a high aspect ratio.
FIG. 14 is a conceptual view showing a conventional SOG step. Normally, a bottled PSZ liquid filled with nitrogen is commercially available. When a bottle cap is opened at a time of a used PSZ bottle being replaced by a new one, the air never fails to enter the bottles. In addition, during the replacement, the air may possibly enter a PSZ liquid supply nozzle from a tip end of the PSZ liquid supply nozzle. If so, the PSZ liquid unavoidably contacts with the air.
The PSZ developed to be silicified at a temperature as low as about several hundred Celsius (° C.) can react with water and oxygen as represented by Chemical Formula 1, and can be solidified even at a room temperature when being exposed to the atmosphere.—(SiH2NH)n—+2nO→nSiO2+nNH3  (Formula 1)
When the PSZ is solidified in a piping from a PSZ container to a discharge nozzle, the solidified PSZ fixedly adheres onto a semiconductor substrate after being discharged together with the PSZ-coating liquid, thereby disadvantageously causing bulges, divots, and streaks. Even if the solidified PSZ is not formed, the air mixed into the piping and discharged onto the semiconductor substrate as air bubbles may possibly cause the bulges, divots, and streaks. Furthermore, the solidified PSZ may possibly damage the semiconductor substrate and a polishing cloth or cause a contamination during CMP (Chemical Mechanical Polish) process.
When the PSZ remains in the used container, the PSZ reacts with water and oxygen to generate ammonium (NH3) and silane (SiH4). The ammonium and silane bring about considerably serious environmental and safety problems. It is, therefore, difficult to manage and handle the PSZ and the PSZ container in manufacturing of semiconductor products.
In these circumstances, therefore, a semiconductor manufacturing apparatus, which airtightly transports a liquid to be coated on a substrate from a container to a discharge portion and suppresses the liquid from coming in contact with the air when the container is replaced by another one, has been desired.
Furthermore, a liquid container detachable from the semiconductor manufacturing apparatus, which airtightly transports the liquid to be coated on the substrate from the container to the discharge portion and suppresses the liquid from coming in contact with the air when the container is replaced by another one, has been desired.